This project has been resumed after a one year inactive period because of change of personnel. The long range goals of the project are to understand the genomic organization of schistosomes, identify target antigens on the worms and clone genes encoding these antigens for the purpose of vaccine production. During the past year progress was achieved in the following areas: (1) monoclonal antibodies were produced from mice immunized with an irradiated vaccine and an anti-schistosomulum surface monoclonal partially characterized. (2) An adult worm cDNA library was constructed in the expression vector lambda gt-11 and a series of clones identified which express fusion proteins cross-reactive with schistosomula. (3) A genomic alteration was detected in the DNA of schistosomes as a consequence of the induction of resistance to the chemotherapeutic drug hycanthone.